Possible Clues:

• Avant-garde provides art from tragedy
• Exploring the bounds of propriety, as humor
• Even-tempered guy, despite appearances, not this?
• Intentionally controversial
• Brittle BBC boss welcomed by the old in retirement
• Irritable in overheated gym
• Sharply delineated spin's good for a Democrat
• Experiencing jitters and nervousness
• Like provocative art
• Challengingly experimental